Having low levels of alcohol in the blood may protect the brain from the effects of a head injury, a study says.

The University of Toronto team found head injury patients who had drunk low amounts were 24% less likely to die than those who had not had any alcohol.

They said alcohol might one day be used as part of emergency treatment for some head injury patients.

But they said the study, which appears in the journal Archives of Surgery, should not encourage people to drink.

Overall, people are still at much greater risk of dying if they drive while intoxicated

University of Toronto

When the brain suffers a severe injury, it is not just the immediate damage caused by the accident that can cause problems.

Over the next few hours, the body launches a natural defence mechanism which can lead to swelling, inflammation and further destruction of brain cells.

In some cases it is this reaction, called "secondary brain injury", which can kill or leave the victim with severe disabilities.

The researchers believe that alcohol, in small doses, could lessen its impact.

Survival rate

They looked at the records of 1,158 head injury patients treated at local hospitals.

Of these, 418 had alcohol in their bloodstream. When similar types of injury were matched, they found that those with a low or moderate level of alcohol were 24% less likely to die in the hospital compared with those who had not been drinking.

Heavy drinking increased the risk of death substantially - those with high levels of alcohol in their blood were 73% more likely to die than those with no alcohol.

The results were strengthened when the research team carried out a similar survey on patients arriving with chest or abdominal injuries, and could find no relationship between alcohol levels and death.

The findings echo studies in animals which suggested a similar, protective effect, for alcohol.

However, the study authors cautioned that this should not be interpreted as an invitation to drink for the good of your health.

"Overall, people are still at much greater risk of dying if they drive while intoxicated," they wrote.

They suggested that there might be a role for putting severe head injury patients on an alcohol-based drip during resuscitation to improve their chances of recovery.

Spot the difference

Dr Will Townend, a consultant in emergency medicine at Hull Royal Infirmary, said that the "vast majority" of people attending his department had alcohol in their bloodstream.

"Often the problem that we face is that people who are intoxicated, but have only a minor head injury, can appear exactly the same as those who do have a severe injury that needs an urgent operation.

"The level of consciousness is one of the only measures of head injury severity that we have, and it is a challenge to compare the outcomes of those who have been drinking alcohol, and those who haven't.

"A patient who has been drinking may seem to have an equally severe injury to another patient because of the effects of alcohol, but make a better recovery."

Dr Tony Shenton, A&E consultant at Bradford Royal Infirmary, said that it was important the public did not see the study as an invitation to drink alcohol for health reasons.

"There's plenty of evidence that the more alcohol you drink, the more likely you are to be in an accident, and that the accident will be more serious."